OpenTracing Spring Web Instrumentation
This library provides instrumentation for Spring Web applications (Boot, MVC and WebFlux). It creates tracing data for
server requests and also client requests (RestTemplate
, AsyncRestTemplate
and WebClient
).
opentracing-spring-cloud
Comparison withAs it was mentioned above, this library traces only inbound/outbound HTTP requests. If you would like to
get automatically traced different set of technologies e.g. spring-cloud-netflix
, JMS or even more then
use project opentracing-spring-cloud instead.
For reactive applications, it is especially recommended to use reactor
tracing from
opentracing-spring-cloud, as that will ensure
that the Span
is activated in reactor handler functions. (Without that, one would have to extract the
Span
from the subscriber context.)
How does the server tracing work?
Servlet
Server span is started in Web Servlet Filter,
then tracing interceptor adds spring related tags and logs. There are use case when spring boot invokes a handler after
a request processing in filter finished, in this case interceptor starts a new span as followsFrom
which references the initial span created in the servlet filter.
Reactive
Server span is started in TracingWebFilter
(upon subscription), then onNext()
, onError()
, etc. handlers add Spring WebFlux related tags and logs.
Library versions
Versions 1.x.y, 2.x.y, ... of the library are meant to target Spring Framework 5.x and Spring Boot 2.x while versions 0.x.y are meant to be used with Spring Framework 4.3 and Spring Boot 1.5
Configuration
Spring Boot Auto-configuration
If you are using Spring Boot the easiest way how to configure OpenTracing instrumentation is to use auto-configuration:
<dependency>
<groupId>io.opentracing.contrib</groupId>
<artifactId>opentracing-spring-web-starter</artifactId>
</dependency>
Just provide an OpenTracing tracer bean and all required configuration is automatically
done for you. It also instruments all RestTemplate
, AsyncRestTemplate
, WebClient
and WebClient.Builder
beans.
Manual configuration
Servlet and MVC Server
Configuration needs to add TracingFilter
and TracingHandlerInterceptor
. Both of these classes
are required!
Tracing interceptor can be instantiated manually or injected via CDI, but
it needs bean of type Tracer
configured.
Java based configuration:
@Configuration
@Import({TracingHandlerInterceptor.class})
public class MVCConfiguration extends WebMvcConfigurerAdapter {
@Autowired
private Tracer tracer;
@Override
public void addInterceptors(InterceptorRegistry registry) {
registry.addInterceptor(new TracingHandlerInterceptor(tracer));
}
@Bean
public FilterRegistrationBean tracingFilter() {
TracingFilter tracingFilter = new TracingFilter(tracer);
FilterRegistrationBean filterRegistrationBean = new FilterRegistrationBean(tracingFilter);
filterRegistrationBean.addUrlPatterns("/*");
filterRegistrationBean.setOrder(Integer.MIN_VALUE);
filterRegistrationBean.setAsyncSupported(true);
return filterRegistrationBean;
}
}
XML based configuration can be used too. Filter can be also directly defined in web.xml
.
Reactive Server
Configuration needs to add the TracingWebFilter
bean.
@Configuration
class TracingConfiguration {
@Bean
public TracingWebFilter tracingWebFilter(Tracer tracer) {
return new TracingWebFilter(
tracer,
Integer.MIN_VALUE, // Order
Pattern.compile(""), // Skip pattern
Collections.emptyList(), // URL patterns, empty list means all
Arrays.asList(new WebFluxSpanDecorator.StandardTags(), new WebFluxSpanDecorator.WebFluxTags())
);
}
}
Client
RestTemplate restTemplate = new RestTemplate();
restTemplate.setInterceptors(Collections.singletonList(new TracingRestTemplateInterceptor(tracer)));
// the same applies for AsyncRestTemplate
Reactive Client
WebClient webClient = WebClient.builder()
.filter(new TracingExchangeFilterFunction(tracer, Collections.singletonList(new WebClientSpanDecorator.StandardTags())))
.build();
Access server span
@RequestMapping("/hello")
public String hello(HttpServletRequest request) {
Span serverSpan = tracer.activeSpan();
Span span = tracer.buildSpan("localSpan")
.asChildOf(serverSpan.context())
.start();
try {
// Traced work happens between start() and deactivate();
return "Hello world!";
} finally {
span.finish();
}
}
Development
./mvnw clean install
Release
Follow instructions in RELEASE